From bd48d31b37cbde04b51daec14139f7f10fdf4878 Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel.sanders@imgtec.com>
Date: Tue, 1 Apr 2014 10:35:28 +0000
Subject: [mips] Rewrite MipsAsmParser and MipsOperand.

Summary:
Highlights:
- Registers are resolved much later (by the render method).
  Prior to that point, GPR32's/GPR64's are GPR's regardless of register
  size. Similarly FGR32's/FGR64's/AFGR64's are FGR's regardless of register
  size or FR mode. Numeric registers can be anything.
- All registers are parsed the same way everywhere (even when handling
  symbol aliasing)
  - One consequence is that all registers can be specified numerically
    almost anywhere (e.g. $fccX, $wX). The exception is symbol aliasing
    but that can be easily resolved.
- Removes the need for the hasConsumedDollar hack
- Parenthesis and Bracket suffixes are handled generically
- Micromips instructions are parsed directly instead of going through the
  standard encodings first.
- rdhwr accepts all 32 registers, and the following instructions that previously
  xfailed now work:
    ddiv, ddivu, div, divu, cvt.l.[ds], se[bh], wsbh, floor.w.[ds], c.ngl.d,
    c.sf.s, dsbh, dshd, madd.s, msub.s, nmadd.s, nmsub.s, swxc1
- Diagnostics involving registers point at the correct character (the $)
- There's only one kind of immediate in MipsOperand. LSA immediates are handled
  by the predicate and renderer.

Lowlights:
- Hardcoded '$zero' in the div patterns is handled with a hack.
  MipsOperand::isReg() will return true for a k_RegisterIndex token
  with Index == 0 and getReg() will return ZERO for this case. Note that it
  doesn't return ZERO_64 on isGP64() targets.
- I haven't cleaned up all of the now-unused functions.
  Some more of the generic parser could be removed too (integers and relocs
  for example).
- insve.df needed a custom decoder to handle the implicit fourth operand that
  was needed to make it parse correctly. The difficulty was that the matcher
  expected a Token<'0'> but gets an Imm<0>. Adding an implicit zero solved this.

Reviewers: matheusalmeida, vmedic

Reviewed By: matheusalmeida

Differential Revision: http://llvm-reviews.chandlerc.com/D3222

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205292 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/Mips/Disassembler/MipsDisassembler.cpp | 52 ++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

(limited to 'lib/Target/Mips/Disassembler')

diff --git a/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
index a543840132..fc3b922602 100644
--- a/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
+++ b/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -263,6 +263,11 @@ static DecodeStatus DecodeExtSize(MCInst &Inst,
                                   uint64_t Address,
                                   const void *Decoder);
 
+/// INSVE_[BHWD] have an implicit operand that the generated decoder doesn't
+/// handle.
+template <typename InsnType>
+static DecodeStatus DecodeINSVE_DF(MCInst &MI, InsnType insn, uint64_t Address,
+                                   const void *Decoder);
 namespace llvm {
 extern Target TheMipselTarget, TheMipsTarget, TheMips64Target,
               TheMips64elTarget;
@@ -304,9 +309,54 @@ extern "C" void LLVMInitializeMipsDisassembler() {
                                          createMips64elDisassembler);
 }
 
-
 #include "MipsGenDisassemblerTables.inc"
 
+template <typename InsnType>
+static DecodeStatus DecodeINSVE_DF(MCInst &MI, InsnType insn, uint64_t Address,
+                                   const void *Decoder) {
+  typedef DecodeStatus (*DecodeFN)(MCInst &, unsigned, uint64_t, const void *);
+  // The size of the n field depends on the element size
+  // The register class also depends on this.
+  InsnType tmp = fieldFromInstruction(insn, 17, 5);
+  unsigned NSize = 0;
+  DecodeFN RegDecoder = nullptr;
+  if ((tmp & 0x18) == 0x00) { // INSVE_B
+    NSize = 4;
+    RegDecoder = DecodeMSA128BRegisterClass;
+  } else if ((tmp & 0x1c) == 0x10) { // INSVE_H
+    NSize = 3;
+    RegDecoder = DecodeMSA128HRegisterClass;
+  } else if ((tmp & 0x1e) == 0x18) { // INSVE_W
+    NSize = 2;
+    RegDecoder = DecodeMSA128WRegisterClass;
+  } else if ((tmp & 0x1f) == 0x1c) { // INSVE_D
+    NSize = 1;
+    RegDecoder = DecodeMSA128DRegisterClass;
+  } else
+    llvm_unreachable("Invalid encoding");
+
+  assert(NSize != 0 && RegDecoder != nullptr);
+
+  // $wd
+  tmp = fieldFromInstruction(insn, 6, 5);
+  if (RegDecoder(MI, tmp, Address, Decoder) == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+  // $wd_in
+  if (RegDecoder(MI, tmp, Address, Decoder) == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+  // $n
+  tmp = fieldFromInstruction(insn, 16, NSize);
+  MI.addOperand(MCOperand::CreateImm(tmp));
+  // $ws
+  tmp = fieldFromInstruction(insn, 11, 5);
+  if (RegDecoder(MI, tmp, Address, Decoder) == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+  // $n2
+  MI.addOperand(MCOperand::CreateImm(0));
+
+  return MCDisassembler::Success;
+}
+
   /// readInstruction - read four bytes from the MemoryObject
   /// and return 32 bit word sorted according to the given endianess
 static DecodeStatus readInstruction32(const MemoryObject &region,
-- 
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